Yesterday I recall installing some header updates, just the usual updates available notification, then I click install. Well I used Steam all night to chat with people, then eventually went to sleep. I awoke a bit ago to learn my Steam client is no longer open, and will not launch.

I tried removing it and reinstalling it, but I can't even get past the initial Ubuntu Software Center install. I'm not sure what to do.

I think I have a similar problem. My Ubuntu just upgraded a few things, including the kernel and removed a few libraries on the way. Now I cannot install steam anymore. The software centrer refuses install and gives the error message "libsdl1.2debian:i386 could not be installed".